Crustal fluids and ore genesis

点击翻译按钮获取中文摘要

Although we have made substantial progress in understanding the role of crustal fluids in forming ore deposits, their quantitative modeling has been limited by a lack of data on metal solubility and speciation. The main objective of my research is to help gather some of these data, and use them to develop genetic models for a selection of deposit types. I will focus mainly on the HFSE, Au-Ag, and Co. A basic assumption in such studies is that the ore fluid is liquid water. However, there is evidence that aqueous vapour and hydrocarbons may also play a role in metal transport. Thus, another objective of my research will be to evaluate this possibility. My overall approach will be to carry out complementary studies of natural and experimental systems. Studies will be conducted at the Imiter Ag-Hg deposit, Morocco, to determine why it has the highest Hg concentration of any deposit of its type and no Au, the Banderas epithermal Au deposit, Guatemala, to evaluate the significance of newly discovered ammonium-bearing alteration minerals, Bou Azzer, Morocco, to develop a genetic model for hydrothermal Co deposits, and the Questa deposit, USA, to evaluate vapour transport of Mo. A study will also be conducted in the Flin Flon belt to understand how mesothermal Au deposits are affected by metamorphism, and on Merapi volcano, Indonesia, to evaluate the efficacy of vapour-mediated transport of metals. Studies of HFSE deposits will be continued at Gallinas Mountains and Strange Lake, and Au-Sn-W at Cirotan. These field-based studies will be complemented by ongoing high-temperature metal speciation experiments on aqueous liquids, and solubility experiments to determine the metal transport capabilities of H2O-H2S-HCl gases. Finally, experiments will be conducted to determine the solubility of Au and Pd in crude oil, for possible application to Carlin type deposits, the Witwatersrand and the Kupferschiefer.  The proposed research has the potential to significantly advance understanding of how metallic mineral deposits form, and help guide exploration for these deposits. It could also find important applications in metallurgy, and in addressing problems of atmospheric and groundwater pollution.